Simulation of large sets of mobile computers or other wireless communication devices is difficult because of the computationally intensive models of wireless channels. Parallel simulation would seem to be applicable here because of the large computation granularity, but the location based communication topology makes conservative methods difficult to implement. This paper considers a novel approach to improving lookahead in conservative parallel simulations by differentiating between data flow paths in the simulation. An experimental study shows that for this application, the technique produces a 70% reduction in null message traffic, with only a 25% increase in null message computation overhead, and a consistent improvement in parallel performance